I defeated my first boss today. Holy shit, that was intense! I had been really stocking up on ammo and weapons for a while, and started feeling invincible. Should have known better. One boss fight later and I was out of nearly everything. Just a few rounds left in the chamber, and no grenades or other fun equipment. Time to feel vulnerable again, I guess.
After you finish the first three episodes on any difficulty, you unlock the first 7 Raid missions in the game. These are sort of like Mercenaries mode, but not quite. Raid sends you through one of the maps in the game, telling you to reach the end. I don't know if you have to kill all enemies, but I think so. You meet appropriate enemies for the locale, and as a neat novelty they actually have a health bar like in an RPG. Killing them seems to always net you some loot, mostly more ammo. There's other loot spread across the place, such as ammo and upgrade parts.
There seems to be some randomness to the way the missions work, though I haven't played any of them twice yet. I noticed some enemies had a little icon next to their health bar. One had a small fist, which I assume meant it would deal more damage if it hit me. Another had a symbol that made it faster, which is a real troublesome thing when your ability to move is hampered (yet the controls are more flexible than in other RE games, allowing you to do stuff like move in all directions, though slowly, while shooting). You may stumble across locked doors, which means that one of the enemies in the area has the key and needs to be killed. It may be the last enemy, or it may not. Haven't played enough to be sure.
When you complete missions you are showered with loot. My first mission netted me a magnum and a weapon upgrade, while my second got me two new pistols and more upgrades. You are rated according to several factors, such as time spent in the mission, weapon accuracy and damage. This earns you points, with more points being earned for better scores, and bonus points awarded for achieving certain feats (killing all enemies in the mission, for example). You also gain levels from completing missions. I'm not quite sure what they do yet, apart from letting you use weapons with level requirements. One of my pistols requires level 4, but since I'm level 3 I can't equip it at the moment. A shame too, because it was the one that seemed to fit my playstyle the most. Gives me incentive to keep playing.
You choose your weapon loadout and their upgrades before a mission. You can carry 3 weapons at a time (maybe this can be upgraded later. I don't know), 4 green herbs, 4 grenades, etc. Ammo spent during a mission is permanently
spent. To get it back you must either find new ammo during a mission or purchase a full clip at premium cost in the store. The store is fun and contains a crapload of stuff. It seems to contain a random assortment of things at any time, so you never quite know what you'll find. Some of these items cost points, while others costs coins (as in, the coins you earn from walking around with your 3DS). Here you can purchase new weapons, restock ammo (price depends on the ammo. Filling up your pistol ammo is relatively cheap, while filling up your magnum is hideously expensive), purchase upgrades, and so on.
The upgrades work the same way as in the campaign. Each weapon has a certain amount of upgrade slots. I've seen anything from 1 to 4 slots so far, but I don't doubt there are weapons with more (or maybe even less). You can freely add or remove upgrades from a weapon between missions, so you don't permanently spend them. These upgrades vary quite a lot, with some being more useful for multiplayer than singleplayer and vice-versa. Examples include bonuses to damage and fire rate, chances to stun enemies, aggro reduction (yup, Raid has an aggro mechanic for multiplayer), increased clip size, bigger hitboxes on enemies, and so on. Choosing what to use and on what weapon can be hard, and I've barely even got anything to use yet!
You can also pick and choose from an assortment of characters, each with their own abilities. The three characters I have so far each has two abilities that give 200% reload speed for certain weapons, so the character you choose this early on depends on what weapon loadout you prefer. I picked the guy who gives 200% reload speed for pistols and shotguns for now. You can clearly unlock more characters over time, as well as new costumes for them. You can also adjust their level, though I'm not sure for what purpose.
You also have something called Missions, which are kind of like trophies/achievements that give you something when you accomplish them. There are separate ones for the campaign and for Raid mode, and they can vary wildly. For example, to unlock Raid mode at all you need to complete a mission that requires you to finish the first 3 episodes at Casual difficulty or higher. In the campaign, completing a mission can give you anything from an extra healing herb (useful!) to new weapons, upgrades or costumes. In Raid mode, missions can give you bonus points, new items, new characters, new costumes, etc.
Remember Resident Evil: The Mercenaries 3D? Raid mode in RE: Revelations has more
content than that entire game, and that's not even including the campaign! There seems to be 20 missions, each with several difficulty levels (that you must unlock through play). Add to that the fact that I never really liked Mercenaries (it feels like you have to practice for a long time to achieve even basic successes) but feel like Raid is really fun. It was hard to put away the game today, but my eyes are starting to hurt from the 3D.
If you've got any questions about the game, feel free to ask. I can at least make an effort to ease the waiting time for you people across the pond.